The #71637 prune fix cut one stage of -w startup, but the base-ref
resolution right after it still ran an uncapped-in-practice
'git fetch origin main' (timeout=30) on every launch — and on a flaky
smart-HTTP connection that fetch intermittently stalled to the full 30s,
then cascaded into step 2's SECOND 30s fetch. Measured: back-to-back
fetches of 0.9s, 1.0s, 63.5s on the same box with healthy TLS (~185ms).
_resolve_worktree_base now:
- skips the fetch entirely when FETCH_HEAD is < 5 min old and the
tracking ref exists (repeat launches pay zero network cost)
- caps the fetch at 5s and falls back to the locally-known tracking
ref (labelled 'cached') on timeout/failure instead of cascading into
a second fetch — genuine staleness stays backstopped by the pre-push
stale-base gate
- caps 'git remote show origin' the same way
Worst case drops ~60s -> ~5s; warm path is ~0.02s (was up to 30.8s).
sync_base=False and the offline HEAD fallback are unchanged.
hermes -w created the worktree branch from the standalone clone's HEAD, which
lags origin when the clone isn't freshly updated (it's only refreshed by
hermes update, not per session). Every worktree branch then rooted on a stale
base, so the PR diff GitHub computes against current main ballooned with
unrelated changes and the agent had to discover the staleness at push time and
rebase.
_resolve_worktree_base() now fetches and branches from the freshest available
ref: the current branch's upstream if it tracks one (so a deliberate
feature-branch worktree tracks its own remote), else the remote's default
branch (origin/HEAD), else local HEAD as a fail-soft fallback (offline / no
remote / detached). A bogus 'origin/(unknown)' default is guarded, and worktree
creation retries from HEAD if branching off the remote ref fails — so this is
never worse than the old behavior.
Gated by worktree_sync (default true); set worktree_sync: false to keep the
old branch-from-local-HEAD behavior. The resolved base is printed in the
session banner.
This is the follow-up to the #50319 session, where the standalone clone was
213 commits behind origin and the worktree inherited that stale base.
